Type action



Aug. 10 1926.

H. A. FOOTHORAP TYPE ACTI'ON Filed May 3. 1924 2 Shets-Sheet l gwmnto'o Harryfifoo/horap H. A. FOOTHORAP TYPE ACTION Filed May 5, 1924 2 Sheets-Sheet 2 Aug. 10 1926.

IZ'HPTYW: Foo/horap Patented Aug. 10, 1926.

UNITED STATES HARRY A. FOOTHORAP, OF HARRISBURG,

PENNSYLVANIA, ASSIGNOR 'ro' ELLIOTT- FISHER COMPANY, A CORPORATION OF DELAWARE.

mama: AcrroN.

Application filed May 8,

My invention relates to improvements in type bar actuating mechanism for type writers, particularly typewriters of the so called front strike class, wherein the type is moved upwardly and rearwardly to impact against the front of the platen.

In. mechanism of this character, two factors are primarily essential to produce the ideal type action, viz, the motion transmit- 1 ting elements between the key and the type bar must be so. arranged and constructed that-the inertia of the type bar is overcome by a very light touch upon the key and the movement of the type bar accelerated relative to the movement of the key to effect a staccato blow of the type against the platen. The importance of these essentials in type actuating mechanism is believed to be well understood. in the art and therefore need not be further emphasized herein.

Although various forms of mechanism have been devised with the end in view of accomplishing the results, referred to as particularly desirable, and some are considered commerciall practicable, the are all susceptible of lmprovement, bot as regards construction and operation.

The purpose of my invention, generally speaking, is to provide a simpli ed type 80 bar actuating mechanism which may be more easily operated than other mechanism of this class, that is to say, one in which a' lighter touch is required to overc'ome the inertia of the type bar and to drive the typehome 85 against the platen.

My invention furthermore is directed toward providing a mechanism in'which ease of operation, or lightness of touch, is combined with the proper acceleration of the bar.

As a specific purpose of my invention I- propose to eliminate, in a mechanism of this character, all sub-levers such as bell cranks, commonly used for transmitting motion 4 from the key lever to the ty e bar, by utilizing a better balanced and 'ence more easily operated medium and so connecting it to the key lever and type bar by a simple and compact arrangement of operating de- 60 vices that movement of the type bar is accelerated relative to movement of the key lever and in the proper degree. I

Other and ancillary purposes will presently appear and the nature of my invention a modification of the invention 1924. Serial No. 710,810.

will be more fully understood when the following description and claims are read.

In the drawings forming a part of this specification I have illustrated a preferred form of the invention applied to a front strike typewriter, but it is to be understood that other forms and aplications of the principles of the invention are withinthe spirit thereof and are intended to be comprehended by the present disclosure.

In the drawings:

Fig. 1 is a view partly in elevation and artly in section showing a portion of a ront strike typewriter having my invention applied thereto, the parts being shown in their normal position.

Fig. 2 is a transverse sectional view taken on the line 22-of-Fig. 1' and drawn on an enlarged scale.

Fig. 3 is a view similar to Fig. 1. showin the full stroke position ofthe parts;

ig. 4 is a diagrammatic view illustrating the manner inwhich the type bar is acoeler-' ated relative to the key, and

Fig. 5 is a view in side elevation showing presently described in detail. e

In the drawings the numeral 1 designates one of the key levers, 2, one of thet pe bars and 3, the platen of a front strilze' typewriter as it is usually constructed. As shown in the drawings, in this class of machine the levers 1 and the bars 2 are fulcrumed at their rear ends below the platen 3, as at 4 and 5 respectively, and normally lie in a horizontal position, the type bars 2 being arranged above the key levers 1.

key ever ,1 'to its associated type bar by means of a vertically disposed circularelement arranged intermediate the lever 1 and bar 2, and to so connect a' lever 1 and bar 2 to theelement that the inertia of the type bar is easily overcome and the bar accelerated relative to the lever by a very light touch uponthe key.

The element 6 may be constructed in various ways but preferably it comprises an annulus 7 which. is mounted to oscillate concentrically upon a disc shaped support 8. The contiguous peripheries of the annulus 7 and the suppor 8 are grooved to provide a raceway 9 f0 ball bearings 10, and preferably the support 8 is formed of propose to transmit motion from one two sections 11 and12 which are clamped together in side by side relation by means of an axial stud 13. The stud 13 is threaded as at 14 so that the support 8 may be secured in a fixed osition upon some portion of the machine ase as indicated at 15. Washers 16 which are preferably of resilient character are provided between the sections 11 and 12 so that by tightening the.

screw stud 13 wear in the raceway 9 may be taken up.

Draw rods 17 and 18 connect the annulus 7 with the lever 1 and bar 2 respectively, the arrangement in the normalposition of the parts being as follows:

The rod 17 is substantially vertical and is pivoted at its lower end to the lever 1, as at 19, to one side of the vertical center of the annulus 7. The upper end of the rod 19 is curved to project into a circumferential slot 20 formed in the annulus 7. A pivot pin 21 connects the curved end of the lever 17 'to the circumferential portion of the annulus 7 at a point thereon which 'Will approach a position in vertical alignment with the pivot 19 when the key lever is depressed. As shown in the drawings, this pivot 21 is located above the horizontal center of the annulus and to one side of the vertical center thereof.

The rod 18, at one end, is similarly connected to the circumferential portion of the annulus 7 by a pivot in 22 located above the horizontal center 0 the annulus but upon the opposite side of its vertical center, with respect to the pivot 21. The other end of the rod is pivotally connected, as at 23,

to the heel of the bar 2 below and to the,

rear of the fulcrum 4 thereof. The pivots 22 and 23 are so arranged that they will approach a position in horizontal alignment when the key lever 1 is depressed.

The foregoing parts of the mechanism are yieldingly held in their normal position, with the type bar abutting the usual buffer bar 24, by means of a retractile spring 25, which has itsopposite ends connected respectively, to the annulus 7 and a suitable portion of the frame of the typewriter.

Although I have shown the usual butter bar 24 for limiting the relative movement of the type bar, I may eliminate said bar 111 practising my invention. To this end the rod 17 and annulus 7 may be so relatively arranged that in the normal position of the mechanism the bar 17 abuts the periphery of the annulus 7 as shown in Fig. 5. Consequently under the pull of the spring 24 the annulus tends to cam the bar 1.7 laterally against its pivot 19 upon the lever 1 and is thereby stopped from further movement.

In the operation of my invention when the key lever 1 is depressed the pivot 21 gradually approaches the vertical with respect to the pivot 19 of the lever 17 and movement of the annulus is accelerated, with respect to the movement of the key lever l, to the degree shown approximately in Fig. 4. In Fig. 4 the lines ab and bc represent two equal increments of movement of the type bar 2, or the pivot 19, and the lines (Z@ and e-; indicate corresponding increments of movement of the pivot 21. Obviously, a corresponding acceleration of the pivot 22 occurs, relative to the movement of the a key lever, and is imparted to the heel of the type bar, as shown by the arcs g-h and hz'. 'Movement of the type bar is also accelerated relative to that of the lever as the pivots 22 and 23 approach a position of horizontal alignment. This will be clear, it is believed, without further explanation.

If desired, the degree of acceleration of the type bar may be varied, relative to the key movement, by changing the relative position of the pivots 22 and 23 upon the annulus 7, openings 26 being provided in the annulus 7 .for that purpose. The rod 17 may be lengthened or shortened for this purpose as it comprises two sections 17 and 17 respectively, one being threaded into the other. The rod 18 is provided with a turnbuckle 18 so that it may be similarly adjusted to engage different openings 26 in the annulus 7.

The operation of my invention will be understood, it is believed, from the foregoing description, but it is to be noted that one of the advantages arising from the use of the elementfi results from its form and balance by reason of which its inertiais more easily overcome when moved in either direction than a lever such as a bell crank.

This insures an easy type action by a light touch on the key. Moreover, because of its form and mounting, suflicient momemtum may be imparted to'it by a light sharp blow on the key to assist in throwing the type bar against the platen with a sharp impact and providefor a quick rebound of said bar to prevent blurring of the printing.

What I claim is:

1. In a type action, in combination, a key lever, a type bar, individual links for the lever and the bar, and a rotatable motion transmittingmember to which one end of each of said links is connected, said member being concentrically mounted and circular to impart balance to the action. 1

2. In a type action, in combination, a key lever, a type bar, a rotatable concentrically mounted disc intermediate the key lever and the type bar for transmitting motion from one to the other and sustaining movement of the action, an operative connection between the key lever and the disc, and a link connection between the type bar and the disc the points of connection of the link being so related to the axis of movement of the disc and type bar respectively that movement of the type bar is accelerated by uniform movement of the disc.

3. In a type action, in combination, a key lever, a type bar, a rotatable concentrically mounted disc intermediate the key lever and the type bar for transmitting motion from one to the other and sustaining movement of the action, individual link connections be- 19 tween the disc and the key lever and type bar respectively havin their points of con nection so disposed re ative to the axes of movement of the disc, key lever and type bar that uniform movement of the key lever will impart accelerated movement to the disc and accelerated movement to the type bar relative to the disc.

In testimony whereof I hereunto afiix my signature. v

HARRY A. FOOTHORAP. 

